The present invention is directed to a handle design which permits an instrument such as cutting blade to be securely attached to a handle. More particularly, the present invention is directed to a handle for a saw which remains securely held to a cutting blade under high tensile loads in a cost effective and efficient manner.
An important factor contributing to the pull-out strength of a saw is the method of attachment of the handle to the cutting blade. Material considerations also play a role. Past attempts to improve handle designs have included first positioning a blade shank within a hollowed wooden handle, and then pouring metal into the handle to bind the shank to the wood. Other attempts have included inserting the blade shank into heated rubber and then letting the rubber cool and harden around the shank. Still others have used nuts or rivets to secure the shank to the handle. These methods, however, are not very efficient or cost effective.
Thus, there is a widely recognized need, and it would be advantageous to have, a more cost efficient and effective blade shank and handle attachment construction. Additional advantages of the present invention are described with respect to its specific embodiments discussed below.
To address shortcomings of the conventional designs, the present invention provides a new and improved blade shank and handle construction which reliably secures a cutting blade to a handle, e.g. a saw handle, in a cost effective and convenient manner.
According to further features of the present invention, there is provided a cutting blade and handle construction which requires a small amount of force to secure the cutting blade to the handle and a large force to separate.
According to still another aspect of the present invention, there is provided a device for cutting which is easy to assemble.
According to still further features of the present invention, there is provided a cutting device having a construction which enhances the appearance of the device.
In accordance with one aspect of the present invention, a device for cutting includes a cutting blade made of metal which has a forwardly disposed toothed portion and a rearwardly disposed shank portion terminating in a rearward end surface. The shank portion has a tapered shape and has outwardly extending projections terminating at associated end portions. The projections are spaced along a longitudinal axis of the cutting blade, and the associated end portions have increasing distances from the longitudinal axis as the associated projections are disposed further away from the end surface of the shank portion. The cutting device also includes a handle portion made of plastic material which has a tapered slot defined therein for accommodating the shank portion of the cutting blade such that the projections are fixedly secured within the handle portion.
In accordance with another aspect of the present invention, a device for cutting includes a cutting blade made of metal which has a forwardly disposed toothed portion and a rearwardly disposed tapered shank portion in a terminating in a rearward end surface. A hole is formed in the cutting blade portion. The cutting device also includes a handle portion made of plastic material and provided with a slot defined therein for accommodating the tapered shank portion of the cutting blade to a predetermined depth therein, such that the hole remains forwardly disposed from the handle portion.
In accordance with still another aspect of the present invention, a device for cutting includes a cutting blade made of metal and having a forwardly disposed toothed portion and a rearwardly disposed tapered shank portion. The cutting device also includes a handle portion made of plastic material and provided with a slot defined therein for accommodating the tapered shank portion of the cutting blade, such that the cutting blade can be attached to the handle portion. The handle portion also has a forwardly facing surface surrounding the slot. The slot has an enlarged forward opening, and is configured and positioned to accommodate the toothed portion of the cutting blade, such that at least a portion of a rearward-most tooth is disposed in the enlarged forward opening and rearwardly of the forwardly facing surface.
In still another aspect of the present invention, a method of manufacturing a cutting device includes providing a metal cutting blade having a forwardly disposed toothed portion and a rearwardly disposed shank portion having a plurality of outwardly extending projections. The method further includes providing a plastic handle portion having a slot defined therein, and effecting relative movement of the shank portion of the cutting blade into the slot defined in the handle portion, each of said projections displacing a particular associated portion of plastic material lining said slot, which portion of plastic material is not displaced by another of said projections.
In still a further aspect of the present invention, a method of assembling a device for cutting includes holding a cutting blade with a fixing element inserted through a hole formed in the cutting blade, and securing the cutting blade to a plastic handle portion by pressing a tapered shank portion of the cutting blade to a predetermined depth into a slot formed in the handle portion so as to be fixedly secured therein, the tapered shank portion having outwardly extending projections terminating at associated end portions.
The present invention successfully addresses shortcomings of known cutting blade and handle configurations. Other objects and advantages of the present invention will become apparent from the following claims and detailed description.